Nor'easter could bring season's first wintry mix or snowfall event for Baltimore area

Scott Dance, The Baltimore Sun

A nor'easter expected to sweep up the Mid-Atlantic coast could bring the season's first wintry precipitation, depending on how closely the storm tracks along the shore, meteorologists said.

Forecasters were confident Monday that a storm system would form Tuesday off the Carolinas and brush past the Delmarva peninsula and the New Jersey and New York coasts late Wednesday and early Thursday. The storm could bring about 2 inches of rain and 60-mile-per-hour wind gusts to shores eroded from the remnants of Hurricane Sandy, potentially causing some coastal flooding.

The storm's proximity to the coast will determine whether significant snow falls inland, said Tom Kines, a senior meteorologist with AccuWeather. Temperatures are expected in the lower 30s overnight Wednesday when the storm would pass, according to the National Weather Service.

"We are more confident about storminess along the coast than we are about the snow inland," Kines said. "The question is, how far west can the precipitation get?"

National Oceanic and Atmospheric Administration forecasts said snow was possible from Washington and Frederick counties northeast through eastern Pennsylvania and into upstate New York. With 1-2 inches of rain expected closer to the coastline, a mix of rain and snow is possible in between.

The storm's track depends on other weather systems, including high pressure over the North Atlantic. Storms known as nor'easters are common in the winter when areas of high pressure act as blockades that keep storm systems from moving east and instead squeeze them up the East Coast. When temperatures are low enough, the storms can bring heavy snow across the Northeast.

The nor'easter name comes from the northeasterly winds the storms bring, Kines said, as well as from their typical tracks from the south to the northeast.

The weather service's Baltimore/Washington forecast office is predicting a possible dividing line between rain and snow along Interstate 95, meteorologist Ken Widelski said. The farther west the storm tracks, the more precipitation it could bring, though the ground could be too warm for significant snow accumulation, Widelski said.

Other forecasters predict snow as more likely. Private meteorology organization Foot's Forecast is predicting about 4 inches of snow near Baltimore/Washington International Thurgood Marshall Airport, spokesman Aaron Salter said. If the storm arrives after sunset, snowfall could increase to as much as 6 inches at BWI, Salter said.

"It's going to be a tough one to figure out," Salter said of the storm. "Recently it's been tracking closer [to land]."

Most forecasts do not call for precipitation to fall far enough inland to affect Garrett County, still recovering from 2 feet of heavy, wet snow that fell during Sandy. More than 3,200 customers of utility Potomac Edison in Garrett remained without power as of 5 p.m. Monday.